Examples of a video instrument that presents video to a viewer include a projection-type video instrument that projects video onto a projection plane such as a screen, and a direct-view video instrument that forms, as a viewing target, video on a display surface of a video instrument without performing projection. The projection video instrument is, for example, a projector, and the direct-view video instrument is, for example, a liquid crystal display, a liquid crystal monitor, a LED (light emitting diode) screen, a plasma display, or a CRT (cathode-ray tube) monitor. Among these video instruments, the projector is suitable for presenting video to a plurality of viewers, and is used in a relatively large indoor space such as a conference room or a lecture hall, and recently, in projection mapping in which video is projected onto objects other than a screen in indoor and outdoor spaces. A large LED screen is used for presentation of video to a large audience in a large outdoor place such as a stadium.
In a case of a projection video instrument such as a projector, or a direct-view video instrument, how video delivered from the video instrument appears to a viewer depends on an environment such as a place at which the video instrument is installed. For example, in a case of a projector, video projected from the projector onto a screen depends on the brightness of a viewing environment, and the projected video has a whitish appearance to a viewer in whole in a bright viewing environment. The viewing environment is a use environment in which the video instrument is used, and in particular, the viewing environment is an environment in which video formed by the video instrument is viewed by a viewer. When the light quantity of the video projected from the projector is insufficient as compared to the brightness of the viewing environment, the viewer cannot clearly see the video. In particular, the video projected from the projector appears white in a viewing environment in which intense light such as sun light is incident, and the viewer cannot see the video as intended. The brightness of video at the projection plane changes depending on the performance of a lens that projects video onto the projection plane, the size of video at the projection plane, and the availability of a lens shift function of shifting the lens in a direction orthogonal to the optical axis of the lens that projects video, in the projector. Accordingly, whether video clearly appears to the viewer depends on factors such as the lens performance, the video size, and the availability of the lens shift function.
Since the appearance of video projected from the projector depends on the viewing environment, it is difficult to predict, in advance, how the projected video actually appears. The same argument applies to a direct-view video instrument such as a liquid crystal display or an LED screen. The appearance of video displayed by a direct-view video instrument depends on, for example, the intensity of external light in the viewing environment, but it is difficult to predict, in advance, whether the luminance of the video instrument in an assumed viewing environment is sufficient or not.
Whether video presented to a viewer has a quality enough for viewing also depends on the kind of used video and a level requested as the quality of the video by a user. Thus, whether video from a video instrument that presents video to a viewer has an enough quality for use in an environment in which the video instrument is assumed to be used has been only determined by bringing the video instrument to an actual use place, displaying video through the video instrument, and checking how the displayed video appears.
Disclosed in [PTL 1] is a system that enables appropriate selection of a projector suitable for a viewing environment from among a plurality of types of projectors having, for example, different brightness of a light source, by receiving the model name of a projector, the size of a projection screen, an arrangement of desks and chairs in a viewing area, and the like, and then outputting an optimum size of the viewing area and the availability of lighting when this model is used. However, this system is not configured to perform simulation of how video appears in an actual viewing environment, and thus whether video would appear as intended by a user cannot be checked through the system. Moreover, this system assumes that a projector is used under a particular environment such as a conference room or a classroom, and thus cannot be used in selection of a projector for usage such as projection mapping.
An example disclosing a technology of performing simulation of the appearance of video in a video instrument is [PTL 2]. Disclosed in [PTL 2] is a system that simulates video viewed through a video display device that is a glass-type device designed as a wearable device individually for each user. This system is used to determine whether a video display device used as an optical aid displays AR (augmented reality) video adapted to a visual condition of a user, and thus is not intended to simulate how differently video appears depending on difference in a viewing environment such as environmental light.